1. Field of the Invention
The present invention is related to a so-called standing pouch type self-standing container having wall surfaces formed by a soft sheet in which the bottom portion expands when the container is filled with contents to enable the container to stand on its own, and in particular to a structure for connecting a sheet member and a tubular member in a pouch container.
2. Description of the Prior Art
In the prior art, glass bottles and PET bottles made of plastic have been used as containers for holding beverages and the like.
In a hard container which is typically a PET bottle, the volume of the container itself is not reduced when the contents are reduced. Accordingly, because this hard container has a high stationary property and can form a pressure tight container depending on the shape thereof, it is possible to use such hard container as a pressure tight container for carbonated beverages and the like.
However, in the same manner as glass bottles and the like, hard containers such as PET bottles and the like normally occupy a fixed volume, and the container itself normally takes up a fixed space regardless of the presence or absence of contents. The fact that such hard containers waste space can be understood by imagining the case where a beverage is filled into a container and stored in a refrigerator, for example. Namely, in the case where a 1-liter bottle filled with 200 cc of water is placed in a refrigerator, the bottle wastes a 800 cc volume of space inside the refrigerator.
On the other hand, as people have become more aware of the need to protect the environment in recent years, inexpensive pouch containers have been used by making PET bottles refillable for household cleansers and the like in order to be free from disposable containers. The pouch containers used in such applications are usually self-standing containers referred to as standing pouches because such containers are easy to display in stores.
Recently, pouch containers provided with a tubular pouring port have been used as beverage containers. These pouch containers are soft and collapsible, and because the total volume of the container is reduced when the contents are reduced, the pouch container can be collapsed at the time of disposal, and this serves to reduce the volume of garbage.
However, in the prior art means for joining a soft pouch portion and a hard tubular portion in this type of container, the joint portion can be damaged easily by the stress concentrated on such joint portion regardless of the fact that a sufficient joint strength is not obtained. For this reason, there are no large-volume pouch containers having such prior art structure.